Diagnostic Approach for Pulmonary Arterial Hypertension

Initial Evaluation

The American Thoracic Society recommends that an RVSP of 96mmHg on echocardiography strongly suggests severe pulmonary hypertension, as normal RVSP is typically around 21±4 mmHg with an upper limit of approximately 30 mmHg 3
Echocardiography is an excellent screening tool for PAH, but it may be imprecise in determining actual pressures compared to invasive evaluation, according to the American College of Chest Physicians 1
Echocardiographic findings should be evaluated for associated abnormalities such as right atrial enlargement, right ventricular enlargement, and pericardial effusion, as suggested by the American Heart Association 1

Right heart catheterization is the gold standard for confirming the diagnosis of PAH and provides definitive information regarding pulmonary vasoreactivity testing, as recommended by the American College of Cardiology 4, 2
Comprehensive evaluation should include pulmonary function tests to assess for underlying lung disease, six-minute walk test to establish functional capacity baseline, non-contrast CT scan of the chest or CT angiogram if thromboembolic disease is suspected, ventilation/perfusion (V/Q) scan to evaluate for chronic thromboembolic pulmonary hypertension, screening for sleep apnea, and echocardiography with bubble study if there is suspicion of intracardiac shunts, as suggested by the European Respiratory Society 5

A thorough search for underlying causes of PAH is essential, including collagen vascular disease 5, HIV infection 1, history of anorexigen use 5, pulmonary veno-occlusive disease 2, sleep apnea 5, sarcoidosis 4, and congenital heart disease with systemic-to-pulmonary shunts 1

Elevated RVSP on echocardiography correlates with poor outcomes, with the mortality risk increasing by approximately 40% with every 10 mmHg increase in PA systolic pressure, as reported by the American Thoracic Society 3
The American College of Cardiology recommends that right ventricular function is a critical determinant of outcomes in PAH, and should be carefully assessed during the diagnostic workup, although the strength of evidence for this fact is not provided 1